CN115051146A

CN115051146A - Antenna and electronic device

Info

Publication number: CN115051146A
Application number: CN202210682348.8A
Authority: CN
Inventors: 漆一宏; 于伟; 朱宇; 肖洋
Original assignee: Leader Technology Hengqin Co ltd
Current assignee: Leader Technology Hengqin Co ltd
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2022-09-13

Abstract

The invention provides an antenna and electronic equipment, wherein the antenna comprises a metal sheet, wherein a first hole, a second hole and a connecting slot for communicating the first hole with the second hole are formed in the metal sheet, and the width of the connecting slot is smaller than or equal to the minimum width of the first hole and the second hole; at least one resonance branch extends from the inner edge of at least one of the first hole, the second hole and the connecting slot, the equivalent extension length of the resonance branch is equal to n/4 times the wavelength of the minimum frequency of the antenna, and n is a positive odd number. The main effect of the technical improvement is that the physical size of the antenna is greatly reduced, the antenna is still in a planar structure, the processing is simple, and the used resonant branch can design the antenna into a completely symmetrical structure, so that the problem of directional diagram distortion can be avoided. The substantial reduction in physical size allows the antenna to be used in more compact box routers as well as flat routers.

Description

Antenna and electronic device

Technical Field

The invention relates to the technical field of wireless communication, in particular to an antenna and electronic equipment.

Background

The slot antenna is widely used in engineering practice and has the advantages of low profile, easy integration and good electromagnetic compatibility. Although the slot antenna has excellent electrical performance, the large physical size of the slot antenna is a factor for limiting application scenarios. The characteristics of a classical center-fed slot antenna are extended by the barbi principle, with the smallest 50 Ω matched slot antenna having an electrical size of one wavelength (electrical size means the ratio of the physical size of the antenna converted to the operating wavelength). When the slot antenna is applied to the Wi-Fi field, since the operating frequency is 2.4GHz and the corresponding wavelength is about 12cm, the length of a typical slot for the slot antenna of 2.4GHz is about 90mm, which greatly limits the application of the slot antenna to a router.

The design of the antenna is aimed at deployment on devices such as Wi-Fi routers or wireless Access Point devices (APs). The slot antenna is not the mainstream in the field, and the main reason is that the disposition space of the antenna is reserved for equipment, and the design of the used 'large strip' external antenna can meet the covering requirement and has no obvious defects. However, for a compact design of the square box-shaped router, the small half-wavelength dipole antenna is used, although the size is small, the same size is not as good in electromagnetic compatibility as the slot antenna.

Therefore, how to reduce the size of the antenna on the basis of ensuring the performance of the antenna becomes a technical problem to be solved in the field.

Disclosure of Invention

The antenna design goal of the present invention is to reduce the physical size of the slot antenna to facilitate deployment on a compact Wi-Fi router. In this field, slot antennas are not the mainstream, mainly because the mainstream products accept the design of "large strip/long stick" external antennas, leaving a large space for the antennas themselves. However, for a compactly designed square box-shaped router, the distance between the antenna and the circuit board is very short, and the problems of electromagnetic compatibility and limitation on the size of the antenna are particularly prominent; by introducing the current guide structure, the invention greatly reduces the physical size of the antenna on the premise of ensuring the performance of the antenna, and solves the problem of integration of the slot antenna and small equipment. The invention belongs to the field of antenna miniaturization technology.

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, an embodiment of the present invention provides an antenna, including a metal sheet, where the metal sheet is provided with a first hole, a second hole, and a connection slit that communicates the first hole and the second hole, and a width of the connection slit is less than or equal to a minimum width of the first hole and the second hole;

at least one resonance branch extends from the inner edge of at least one of the first hole, the second hole and the connecting slot, the equivalent extension length of the resonance branch is equal to n/4 times the wavelength of the minimum frequency of the antenna, and n is a positive odd number.

According to the antenna provided by the embodiment of the invention, the resonant branch is arranged, so that the current is forcibly guided to 'more than one path' when the antenna works, the path through which the current passes is prolonged on the premise of not changing the physical size of the antenna, and the effect of reducing the resonant frequency is achieved. Therefore, the antenna of the embodiment of the invention is substantially reduced in size compared with the existing antenna, and the antenna can be used in a more compact box type router and a flat router due to the fact that the physical size is greatly reduced.

Optionally, the metal sheet has a first extension portion and a second extension portion disposed opposite to the first extension portion, and the first extension portion and the second extension portion form the connecting slit therebetween.

Optionally, the first extension part is rectangular, in a shape like a Chinese character 'tu', trapezoidal or rectangular with a chamfer; and/or the second extension part is rectangular, convex, trapezoidal or rectangular with chamfer angles.

Optionally, the metal sheet is symmetrical left and right, and/or the metal sheet is symmetrical up and down.

Optionally, the resonance branches are arranged in the first hole and the second hole, and the resonance branches are U-shaped or mountain-shaped; alternatively, the first and second electrodes may be,

the connecting slot is internally provided with the resonance branch knot which is U-shaped or V-shaped.

Optionally, the resonant minor matters are arranged in the first hole and the second hole;

the resonance branch in the first hole comprises a hook-shaped branch and an L-shaped branch, the hook-shaped branch is connected to the inner edge of the first hole, and the L-shaped branch is connected to the hook-shaped branch;

the resonance branch in the second hole comprises a hook-shaped branch and an L-shaped branch, the hook-shaped branch is connected to the inner side of the second hole, and the L-shaped branch is connected to the hook-shaped branch.

the resonance branch in the first hole comprises a long-strip branch and a U-shaped branch, one end of the long-strip branch is connected to the inner side of the first hole, and the other end of the long-strip branch is connected to the middle of the U-shaped branch;

downthehole resonance branch knot of second includes rectangular branch knot and U-shaped branch knot, the one end of rectangular branch knot connect in the interior limit in second hole, the other end connect in the middle part of U-shaped branch knot.

Optionally, the first extension portion is rectangular, and the second extension portion is trapezoidal;

the two sides of the first extension part are respectively provided with one resonance branch, and the resonance branches positioned on the two sides of the first extension part are in a hook shape or a U shape.

Optionally, two sides of the second extension portion are respectively provided with one resonance branch, and the resonance branches located at two sides of the second extension portion are L-shaped.

Optionally, the first extension part is in a shape of a Chinese character 'tu', and the second extension part is in a shape of a trapezoid;

the two sides of the first extension part are respectively provided with the resonance branch, and a hook-shaped gap and an L-shaped gap communicated with the hook-shaped gap are arranged between the resonance branch and the first extension part.

Optionally, the first hole and/or the second hole are/is in a shape of a Chinese character 'tu', the resonance branch is arranged in each of the first hole and the second hole, and the resonance branch is in a hook shape.

Optionally, the edge of the first extension and/or the second extension is curvilinear.

The embodiment of the invention also provides electronic equipment comprising the antenna. The electronic equipment of the embodiment of the invention can be a mobile phone, a tablet computer, a router and the like.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

Fig. 1-10 are schematic structural diagrams of metal sheets of antennas according to different embodiments of the present invention;

fig. 11 is a diagram illustrating parameters of a simulated antenna S11 when resonant stubs of the antenna have different lengths according to an embodiment of the present invention.

Reference numerals:

100-a metal sheet; 101-a first extension; 102-a second extension;

10-a first well; 20-a second well; 30-connecting and slotting;

40-resonant minor matters; 401-a third extension; 41-hook branch knot; 42-L shaped branch; 43-long branch knots; 44-U-shaped branch.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The currently mainstream Wi-Fi5 technology uses two frequency bands, namely 2.4GHz (2400 MHz-2500 MHz) and 5GHz (5150 MHz-5850 MHz). The new Wi-Fi6E technology in the two years uses a new 6GHz frequency band (5950MHz-7150MHz), and the technology mentioned in the embodiment of the invention mainly solves the problem of miniaturization of the antenna size on the premise of ensuring the antenna performance.

Referring to fig. 1 to 10, the antenna of the embodiment of the present invention mainly includes a metal sheet 100, and the performance of the antenna mainly depends on the structure of the metal sheet 100, which is the main content of the present application, so the antenna of the embodiment of the present invention will be mainly described with reference to the metal sheet 100 in this embodiment.

Specifically, the metal sheet 100 is provided with a first hole 10, a second hole 20 and a connecting slit 30 communicating the first hole 10 and the second hole 20, and the width of the connecting slit 30 is less than or equal to the minimum width of the first hole 10 and the second hole 20; the location of the connecting slot 30 may set the feed point of the antenna.

At least one resonance branch 40 extends from the inner edge of at least one of the first hole 10, the second hole 20 and the connecting slot 30, that is, at least one resonance branch 40 may extend from the inner edge of the first hole 10, at least one resonance branch 40 may also extend from the inner edge of the second hole 20, at least one resonance branch 40 may also extend from the inner edge of the connecting slot 30, at least one resonance branch 40 may also extend from the inner edge of the first hole 10 and the second hole 20, at least one resonance branch 40 may also extend from the inner edge of the first hole 10 and the connecting slot 30, at least one resonance branch 40 may also extend from the inner edge of the second hole 20 and the connecting slot 30, or at least one resonance branch 40 may also extend from the inner edge of the first hole 10, the second hole 20 and the connecting slot 30.

Wherein the equivalent extension length of the resonant stub 40 is equal to n/4 times the wavelength of the minimum frequency of the antenna, n is a positive odd number, for example: n is 1, 3, 5, 7, etc. That is, the equivalent extension length of the resonant stub 40 may be 1/4 times of the wavelength of the minimum frequency of the antenna, or 3/4 times of the wavelength of the minimum frequency of the antenna, where the minimum frequency of the antenna, i.e., the frequency band with the minimum frequency in all frequency bands of the antenna, is, for example, in Wi-Fi5 technology, the used operating frequency bands are two frequency bands of 2.4GHz (2400 MHz-2500 MHz) and 5GHz (5150 MHz-5850 MHz). Then the minimum frequency band is 2.4 GHz.

The purpose of adding the resonant branch 40 is to lead the current to forcibly go "one more way" when the antenna works, so that the path that the current goes is prolonged on the premise of not changing the physical size of the antenna, and the effect of reducing the resonant frequency is achieved.

In some embodiments, the 2.4GHz slot antenna has a size of 26mm × 30mm, and if the resonant stub 40 is not provided, the resonant frequency of the resonant antenna is 3.8GHz in full-wave calculation; and an extra added resonance branch 40 is introduced, so that the working frequency can cover a 2.4GHz frequency band. Fig. 11 shows the parameters of the simulated antenna S11 when the branches have different lengths (the branch length affects the resonant frequency, and the longer the branch length, the lower the frequency).

In some embodiments, the resonance branch can guide current only when resonance is achieved, and in a 5GHz frequency band, the length of the new resonance branch 40 which grows out is changed into a half-wavelength structure, at this time, the circuit is equivalent to disconnection, the current on the resonance branch 40 is greatly reduced, and the effect of guiding current is no longer achieved. Therefore, the introduced resonance branch can reduce the resonance frequency of the low-frequency point and has little influence on the high-frequency resonance point. Meanwhile, since the resonant branch is a metal extension of the slot antenna, the actual length may be slightly shorter than a quarter wavelength, for example, in the embodiment, the length of the resonant branch 40 is 18.5mm, the equivalent dielectric constant of the dielectric plate is 1.52, which is calculated to be about one fifth wavelength and slightly shorter than a quarter wavelength.

The resonant stubs 40 are less restrictive as they need only be provided for the purpose of resonance. The method mainly has the following characteristics:

1. the beginning of the extension of the resonant stub 40 may be at the position of the current zero. The current distribution of the whole-wavelength slot antenna is clear, and the diversion structure only diverts the part with small amplitude near the zero point to the newly added resonant branch 40. The resonant stub 40 designed in this way has a weak current, and the shape and layout of the resonant stub 40 have minimal impact on the performance of the original antenna. Even a slight offset will only affect the matching of the antenna but not the effect of the size reduction.

2. The number and orientation of the resonant stubs 40 can be varied, and can be multiple symmetrical or multiple asymmetrical. Because the resonance branch 40 mainly plays a role in drainage, even only one resonance branch 40 can also play a role in drainage, the resonance branch 40 used up and down, left and right can not be influenced even if the resonance branch 40 is different in shape (the symmetrical design can have a better radiation pattern). The shape of the slit can be changed for optimizing the matching performance, and the shape is not limited and does not need to be a triangular gradual change. The gaps are not necessarily symmetrical up, down, left and right. The additional resonant stubs 40 do not need to be pulled far from the metal body part of the antenna as long as the equivalent length meets the above requirements.

3. As long as the total electrical size (namely the equivalent extension length) is not changed, the branches can be longer on the branches, and the result is not influenced by a plurality of branches.

The antenna structure of the present invention will be described below with reference to several specific embodiments.

Referring to fig. 1-10, in some embodiments, the metal sheet 100 has a first extension 101 and a second extension 102 opposite to the first extension 101, and the connecting slit 30 is formed between the first extension 101 and the second extension 102.

The shape of the first extension 101 and the second extension 102 may be variously exemplified, for example: the first extension part 101 is rectangular, convex, trapezoidal or rectangular with chamfer; the second extension 102 may also be rectangular, "convex," trapezoidal, or rectangular with chamfers.

In some embodiments, referring to fig. 1-10, the metal sheet 100 may be symmetrical left and right, and referring to fig. 1-5 and 10, the metal sheet 100 may be symmetrical left and right and also symmetrical up and down.

Referring to fig. 1, the resonant branches 40 are disposed in the first hole 10 and the second hole 20, and the resonant branches 40 are U-shaped, and referring to fig. 4, the resonant branches 40 are disposed in the first hole 10 and the second hole 20, and the resonant branches 40 are in a shape of a Chinese character 'shan'.

Referring to fig. 2, a resonant branch 40 is arranged in the connecting slit 30, the resonant branch 40 is U-shaped, and a third extension 401 is arranged in the U-shape, wherein the third extension 401 is rectangular;

referring to fig. 3, a resonant branch 40 is disposed in the connecting slit 30, the resonant branch 40 is V-shaped, and a third extending portion 401 is disposed in the V-shape, where the third extending portion 401 is triangular.

Referring to fig. 5, the resonant branches 40 are disposed in both the first hole 10 and the second hole 20; the resonance branch 40 in the first hole 10 comprises a hook branch 41 and an L branch 42, the hook branch 41 is connected to the inner side of the first hole 10, and the L branch 42 is connected to the hook branch 41; the resonant stub 40 in the second hole 20 includes a hook stub 41 and an L stub 42, the hook stub 41 being connected to the inner edge of the second hole 20, and the L stub 42 being connected to the hook stub 41. This is the case when the structure is directly on the long branches. On the basis, the number of the branches can be continuously increased, and the shapes of the branches can be changed.

Referring to fig. 4, the resonant branches 40 are disposed in both the first hole 10 and the second hole 20; the resonance branch 40 in the first hole 10 comprises a long-strip branch 43 and a U-shaped branch 44, one end of the long-strip branch 43 is connected to the inner edge of the first hole 10, the other end of the long-strip branch 43 is connected to the middle part of the U-shaped branch 44, and the long-strip branch 43 and the U-shaped branch 44 form a Chinese character 'shan'; the resonance branch 40 in the second hole 20 comprises a long-strip branch 43 and a U-shaped branch 44, one end of the long-strip branch 43 is connected to the inner side of the second hole 20, the other end of the long-strip branch 43 is connected to the middle of the U-shaped branch 44, and the long-strip branch 43 and the U-shaped branch 44 form a Chinese character 'shan'.

Referring to fig. 6, the first extension 101 is rectangular, and the second extension 102 is trapezoidal; two sides of the first extension part 101 are respectively provided with a resonance branch 40, and the resonance branches 40 at two sides of the first extension part 101 are in a hook shape or a U shape.

In some embodiments, referring to fig. 7, the first extension 101 is rectangular and the second extension 102 is trapezoidal; two sides of the first extension part 101 are respectively provided with a resonance branch 40, and the resonance branches 40 positioned at two sides of the first extension part 101 are hook-shaped; two resonant branches 40 are respectively arranged on two sides of the second extension part 102, and the resonant branches 40 on two sides of the second extension part 102 are L-shaped.

In some embodiments, referring to fig. 8, the first extension 101 is rectangular and the second extension 102 is trapezoidal; the two sides of the first extension part 101 are respectively provided with a resonance branch 40, and a hook-shaped gap and a U-shaped gap communicated with the hook-shaped gap are arranged between the resonance branch 40 and the first extension part 101.

In some embodiments, referring to fig. 9, the first extension 101 has a "convex" shape and the second extension 102 has a trapezoidal shape; the two sides of the first extension part 101 are respectively provided with a resonance branch 40, and a hook-shaped gap and an L-shaped gap communicated with the hook-shaped gap are arranged between the resonance branch 40 and the first extension part 101.

In some embodiments, the first aperture 10 and/or the second aperture 20 are "embossed," for example: referring to fig. 10, the first hole 10 and the second hole 20 are both in a shape of a "convex", the resonant branches 40 are disposed in the first hole 10 and the second hole 20, and the resonant branches 40 are in a hook shape.

Further, the edge of the first extension 101 and/or the second extension 102 is curved.

The antenna of each embodiment keeps the advantages of high radiation efficiency, good electromagnetic compatibility and the like of the slot antenna. The main effect of the technical improvement is that the physical size of the antenna is greatly reduced, the antenna is still in a planar structure, the processing is simple, and the used resonant branch 40 can design the antenna into a completely symmetrical structure, so that the problem of directional diagram distortion can be avoided. The substantial reduction in physical size allows the antenna to be used in more compact box routers as well as flat routers.

The embodiment of the invention also provides electronic equipment comprising the antenna of any one of the embodiments. The electronic device may be a mobile phone, a tablet computer, a router, etc.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. An antenna is characterized by comprising a metal sheet (100), wherein the metal sheet (100) is provided with a first hole (10), a second hole (20) and a connecting slot (30) for communicating the first hole (10) with the second hole (20), and the width of the connecting slot (30) is less than or equal to the minimum width of the first hole (10) and the second hole (20);

at least one resonance branch (40) extends from the inner edge of at least one of the first hole (10), the second hole (20) and the connecting slot (30), the equivalent extension length of the resonance branch (40) is equal to n/4 times the wavelength of the minimum frequency of the antenna, and n is a positive odd number.

2. The antenna according to claim 1, characterized in that the metal sheet (100) has a first extension (101) and a second extension (102) arranged opposite to the first extension (101), the first extension (101) and the second extension (102) forming the connecting slit (30) therebetween.

3. The antenna of claim 2, wherein the first extension (101) is rectangular, "dogleg," trapezoidal, "or rectangular with chamfers; and/or the second extension part (102) is rectangular, convex, trapezoidal or rectangular with chamfer angles.

4. The antenna according to claim 2, characterized in that the metal sheet (100) is left-right symmetric, and/or the metal sheet (100) is up-down symmetric.

5. The antenna according to any of claims 2-4, wherein the resonant stub (40) is disposed in each of the first hole (10) and the second hole (20), and the resonant stub (40) is U-shaped or E-shaped; alternatively, the first and second electrodes may be,

the resonance branch sections (40) are arranged in the connecting slots (30), and the resonance branch sections (40) are U-shaped or V-shaped.

6. An antenna according to any of claims 2-4, characterized in that the resonant stub (40) is arranged in both the first hole (10) and the second hole (20);

the resonant stub (40) in the first hole (10) comprises a hook stub (41) and an L stub (42), the hook stub (41) is connected to the inner edge of the first hole (10), and the L stub (42) is connected to the hook stub (41);

the resonant stub (40) in the second bore (20) comprises a hook stub (41) and an L stub (42), the hook stub (41) being connected to the inner edge of the second bore (20), the L stub (42) being connected to the hook stub (41).

7. An antenna according to any of claims 2-4, characterized in that the resonant stub (40) is arranged in both the first hole (10) and the second hole (20);

the resonance branch (40) in the first hole (10) comprises a long-strip branch (43) and a U-shaped branch (44), one end of the long-strip branch (43) is connected to the inner edge of the first hole (10), and the other end of the long-strip branch is connected to the middle part of the U-shaped branch (44);

resonance minor matters (40) in second hole (20) are including rectangular minor matters (43) and U-shaped minor matters (44), the one end of rectangular minor matters (43) connect in the interior limit of second hole (20), the other end connect in the middle part of U-shaped minor matters (44).

8. The antenna according to any of claims 2-4, wherein said first extension (101) is rectangular and said second extension (102) is trapezoidal;

the two sides of the first extension part (101) are respectively provided with one resonance branch (40), and the resonance branches (40) on the two sides of the first extension part (101) are in a hook shape or a U shape.

9. The antenna of claim 8, wherein one of the resonant stubs (40) is disposed on each side of the second extension portion (102), and the resonant stubs (40) on each side of the second extension portion (102) are L-shaped.

10. The antenna according to any of claims 2-4, characterized in that said first extension (101) is "convex" shaped and said second extension (102) is trapezoidal shaped;

the two sides of the first extension part (101) are respectively provided with the resonance branch (40), and a hook-shaped gap and an L-shaped gap communicated with the hook-shaped gap are arranged between the resonance branch (40) and the first extension part (101).

11. An antenna according to any of claims 2 to 4, characterized in that the first hole (10) and/or the second hole (20) are/is shaped like a letter "dogbone", the resonant stub (40) being arranged in both the first hole (10) and the second hole (20), the resonant stub (40) being hook-shaped.

12. An antenna according to claim 11, characterized in that the edge of the first extension (101) and/or the second extension (102) is curved.

13. An electronic device, characterized in that it comprises an antenna according to any of claims 1-12.